This invention relates to a feeding system for a crop harvester and, in particular, to means for converging and concentrating crop material as it is conveyed from a gathering or harvesting means to a crop processing means of the harvester.
It is the general nature of mobile crop harvesters which includes crop processing means, to transfer crop material from the field to the crop processing means as the harvester advances by means of a gathering and conveying combination often called a header. Typically, and especially in combine harvesters for handling grain and the like, where the crop processing means is commonly referred to as a separator, the transverse span or width of the gatherer is much greater than that of the separator (and particularly the inlet to the separator) and the gatherer is required to converge crop material to the inlet of a feeder house for conveying it from the gatherer to the inlet of the separator. Typically, the feeder house is parallel sided and its conveying elements move material linearly from the gatherer to the separator without further convergence. Lateral convergence of material for delivery to the separator, therefore, is done essentially in one stage and all of it by the gatherer. Such systems, involving sudden concentration and abrupt change of direction of material at the entrance to the feeder house (if the full width of the parallel-sided feeder house conveyor is to be used), are inherently inefficient, but because of their relative simplicity, their inefficiencies have been tolerated. However, with the desire for ever greater harvester productivity, achieved through wider gatherers and/or higher forward speeds and requiring convergence and concentration of material at ever greater rates, improved crop material handling at the entrance to and within the feeder house is needed. The need is particularly great, for example, in a combine harvester using a fore-and-aft disposed axial flow rotary separator which typically has a high specific capacity in terms of separator overall dimensions and may preferably be fed with a relatively narrow concentrated stream of crop material.
In one such harvester, as disclosed in U.S. Pat. No. 4,170,235, Ashton et al, the approach to high capacity is made by using a relatively wide feeder house and feeder house conveyor and interposing between the conveyor and separator inlet a relatively large diameter transverse converging conveyor with a central beater portion. However, this arrangement only postpones until it can be postponed no longer completion of the simple lateral convergence of material begun by the lateral or transverse conveyor of a gatherer such as the platform auger of the grain platform disclosed by Ashton. By postponing the convergence and concentration of material, an inconveniently bulky feeder house is still required.
It is also known, as disclosed in U.S. Pat. No. 4,087,953, Wilson et al (sharing a common assignee with the present application), to improve the efficiency of transfer of crop material from a gatherer to a feeder house conveyor system of high specific capacity by using a simple transversely oriented, paddle-type beater working in tandem with the central discharge portion of the gatherer transverse conveyor auger. When an efficient high specific capacity feeder house conveyor, such as the dual auger arrangement of Wilson et al, is used, it is possible to provide the substantial increases in material handling capacity now being demanded with relatively small increases in the overall cross-sectional dimensions of the feeder house or at least of the linear or straight line conveying portion of it. However, such substantial increases in capacity means that ever larger masses of crop material must be transferred from the gatherer to the feeder house. Neither Ashton et al or Wilson et al recognize the opportunities for improvements in material handling efficiency present at the junction between gatherer and feeder house.